/* Copyright (c) 2009-2010 Xiph.Org Foundation
   Written by Jean-Marc Valin */
   /*
	  Redistribution and use in source and binary forms, with or without
	  modification, are permitted provided that the following conditions
	  are met:

	  - Redistributions of source code must retain the above copyright
	  notice, this list of conditions and the following disclaimer.

	  - Redistributions in binary form must reproduce the above copyright
	  notice, this list of conditions and the following disclaimer in the
	  documentation and/or other materials provided with the distribution.

	  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
	  OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "celt_lpc.h"
#include "stack_alloc.h"
#include "mathops.h"
#include "pitch.h"

void _celt_lpc(
	opus_val16       *_lpc, /* out: [0...p-1] LPC coefficients      */
	const opus_val32 *ac,  /* in:  [0...p] autocorrelation values  */
	int          p
	)
{
	int i, j;
	opus_val32 r;
	opus_val32 error = ac[0];
#ifdef FIXED_POINT
	opus_val32 lpc[LPC_ORDER];
#else
	float *lpc = _lpc;
#endif

	for (i = 0; i < p; i++)
		lpc[i] = 0;
	if (ac[0] != 0)
	{
		for (i = 0; i < p; i++) {
			/* Sum up this iteration's reflection coefficient */
			opus_val32 rr = 0;
			for (j = 0; j < i; j++)
				rr += MULT32_32_Q31(lpc[j], ac[i - j]);
			rr += SHR32(ac[i + 1], 3);
			r = -frac_div32(SHL32(rr, 3), error);
			/*  Update LPC coefficients and total error */
			lpc[i] = SHR32(r, 3);

			for (j = 0; j < (i + 1) >> 1; j++)
			{
				opus_val32 tmp1, tmp2;
				tmp1 = lpc[j];
				tmp2 = lpc[i - 1 - j];
				lpc[j] = tmp1 + MULT32_32_Q31(r, tmp2);
				lpc[i - 1 - j] = tmp2 + MULT32_32_Q31(r, tmp1);
			}

			error = error - MULT32_32_Q31(MULT32_32_Q31(r, r), error);
			/* Bail out once we get 30 dB gain */
#ifdef FIXED_POINT
			if (error < SHR32(ac[0], 10))
				break;
#else
			if (error < .001f*ac[0])
				break;
#endif
		}
	}
#ifdef FIXED_POINT
	for (i = 0; i < p; i++)
	{
		_lpc[i] = ROUND16(lpc[i], 16);
	}
#endif
}


void celt_fir_c(
	const opus_val16 *_x,
	const opus_val16 *num,
	opus_val16 *_y,
	int N,
	int ord,
	opus_val16 *mem,
	int arch)
{
	int i, j;
	VARDECL(opus_val16, rnum);
	VARDECL(opus_val16, x);
	SAVE_STACK;

	ALLOC(rnum, ord, opus_val16);
	ALLOC(x, N + ord, opus_val16);
	for (i = 0; i < ord; i++)
		rnum[i] = num[ord - i - 1];
	for (i = 0; i < ord; i++)
		x[i] = mem[ord - i - 1];
	for (i = 0; i < N; i++)
		x[i + ord] = _x[i];
	for (i = 0; i < ord; i++)
		mem[i] = _x[N - i - 1];
#ifdef SMALL_FOOTPRINT
	(void)arch;
	for (i = 0; i < N; i++)
	{
		opus_val32 sum = SHL32(EXTEND32(_x[i]), SIG_SHIFT);
		for (j = 0; j < ord; j++)
		{
			sum = MAC16_16(sum, rnum[j], x[i + j]);
		}
		_y[i] = SATURATE16(PSHR32(sum, SIG_SHIFT));
	}
#else
	for (i = 0; i < N - 3; i += 4)
	{
		opus_val32 sum[4] = { 0,0,0,0 };
		xcorr_kernel(rnum, x + i, sum, ord, arch);
		_y[i] = SATURATE16(ADD32(EXTEND32(_x[i]), PSHR32(sum[0], SIG_SHIFT)));
		_y[i + 1] = SATURATE16(ADD32(EXTEND32(_x[i + 1]), PSHR32(sum[1], SIG_SHIFT)));
		_y[i + 2] = SATURATE16(ADD32(EXTEND32(_x[i + 2]), PSHR32(sum[2], SIG_SHIFT)));
		_y[i + 3] = SATURATE16(ADD32(EXTEND32(_x[i + 3]), PSHR32(sum[3], SIG_SHIFT)));
	}
	for (; i < N; i++)
	{
		opus_val32 sum = 0;
		for (j = 0; j < ord; j++)
			sum = MAC16_16(sum, rnum[j], x[i + j]);
		_y[i] = SATURATE16(ADD32(EXTEND32(_x[i]), PSHR32(sum, SIG_SHIFT)));
	}
#endif
	RESTORE_STACK;
}

void celt_iir(const opus_val32 *_x,
	const opus_val16 *den,
	opus_val32 *_y,
	int N,
	int ord,
	opus_val16 *mem,
	int arch)
{
#ifdef SMALL_FOOTPRINT
	int i, j;
	(void)arch;
	for (i = 0; i < N; i++)
	{
		opus_val32 sum = _x[i];
		for (j = 0; j < ord; j++)
		{
			sum -= MULT16_16(den[j], mem[j]);
		}
		for (j = ord - 1; j >= 1; j--)
		{
			mem[j] = mem[j - 1];
		}
		mem[0] = ROUND16(sum, SIG_SHIFT);
		_y[i] = sum;
	}
#else
	int i, j;
	VARDECL(opus_val16, rden);
	VARDECL(opus_val16, y);
	SAVE_STACK;

	celt_assert((ord & 3) == 0);
	ALLOC(rden, ord, opus_val16);
	ALLOC(y, N + ord, opus_val16);
	for (i = 0; i < ord; i++)
		rden[i] = den[ord - i - 1];
	for (i = 0; i < ord; i++)
		y[i] = -mem[ord - i - 1];
	for (; i < N + ord; i++)
		y[i] = 0;
	for (i = 0; i < N - 3; i += 4)
	{
		/* Unroll by 4 as if it were an FIR filter */
		opus_val32 sum[4];
		sum[0] = _x[i];
		sum[1] = _x[i + 1];
		sum[2] = _x[i + 2];
		sum[3] = _x[i + 3];
		xcorr_kernel(rden, y + i, sum, ord, arch);

		/* Patch up the result to compensate for the fact that this is an IIR */
		y[i + ord] = -ROUND16(sum[0], SIG_SHIFT);
		_y[i] = sum[0];
		sum[1] = MAC16_16(sum[1], y[i + ord], den[0]);
		y[i + ord + 1] = -ROUND16(sum[1], SIG_SHIFT);
		_y[i + 1] = sum[1];
		sum[2] = MAC16_16(sum[2], y[i + ord + 1], den[0]);
		sum[2] = MAC16_16(sum[2], y[i + ord], den[1]);
		y[i + ord + 2] = -ROUND16(sum[2], SIG_SHIFT);
		_y[i + 2] = sum[2];

		sum[3] = MAC16_16(sum[3], y[i + ord + 2], den[0]);
		sum[3] = MAC16_16(sum[3], y[i + ord + 1], den[1]);
		sum[3] = MAC16_16(sum[3], y[i + ord], den[2]);
		y[i + ord + 3] = -ROUND16(sum[3], SIG_SHIFT);
		_y[i + 3] = sum[3];
	}
	for (; i < N; i++)
	{
		opus_val32 sum = _x[i];
		for (j = 0; j < ord; j++)
			sum -= MULT16_16(rden[j], y[i + j]);
		y[i + ord] = ROUND16(sum, SIG_SHIFT);
		_y[i] = sum;
	}
	for (i = 0; i < ord; i++)
		mem[i] = _y[N - i - 1];
	RESTORE_STACK;
#endif
}

int _celt_autocorr(
	const opus_val16 *x,   /*  in: [0...n-1] samples x   */
	opus_val32       *ac,  /* out: [0...lag-1] ac values */
	const opus_val16       *window,
	int          overlap,
	int          lag,
	int          n,
	int          arch
	)
{
	opus_val32 d;
	int i, k;
	int fastN = n - lag;
	int shift;
	const opus_val16 *xptr;
	VARDECL(opus_val16, xx);
	SAVE_STACK;
	ALLOC(xx, n, opus_val16);
	celt_assert(n > 0);
	celt_assert(overlap >= 0);
	if (overlap == 0)
	{
		xptr = x;
	}
	else {
		for (i = 0; i < n; i++)
		{
			xx[i] = x[i];
		}
		for (i = 0; i < overlap; i++)
		{
			xx[i] = MULT16_16_Q15(x[i], window[i]);
			xx[n - i - 1] = MULT16_16_Q15(x[n - i - 1], window[i]);
		}
		xptr = xx;
	}
	shift = 0;
#ifdef FIXED_POINT
	{
		opus_val32 ac0;
		ac0 = 1 + (n << 7);
		if (n & 1) ac0 += SHR32(MULT16_16(xptr[0], xptr[0]), 9);
		for (i = (n & 1); i < n; i += 2)
		{
			ac0 += SHR32(MULT16_16(xptr[i], xptr[i]), 9);
			ac0 += SHR32(MULT16_16(xptr[i + 1], xptr[i + 1]), 9);
		}
		shift = celt_ilog2(ac0) - 30 + 10;
		shift = (shift) / 2;
		if (shift > 0)
		{
			for (i = 0; i < n; i++)
			{
				xx[i] = PSHR32(xptr[i], shift);
			}
			xptr = xx;
		}
		else
			shift = 0;
	}
#endif
	celt_pitch_xcorr(xptr, xptr, ac, fastN, lag + 1, arch);
	for (k = 0; k <= lag; k++)
	{
		for (i = k + fastN, d = 0; i < n; i++)
			d = MAC16_16(d, xptr[i], xptr[i - k]);
		ac[k] += d;
	}
#ifdef FIXED_POINT
	shift = 2 * shift;
	if (shift <= 0)
		ac[0] += SHL32((opus_int32)1, -shift);
	if (ac[0] < 268435456)
	{
		int shift2 = 29 - EC_ILOG(ac[0]);
		for (i = 0; i <= lag; i++)
		{
			ac[i] = SHL32(ac[i], shift2);
		}
		shift -= shift2;
	}
	else if (ac[0] >= 536870912)
	{
		int shift2 = 1;
		if (ac[0] >= 1073741824)
			shift2++;
		for (i = 0; i <= lag; i++)
		{
			ac[i] = SHR32(ac[i], shift2);
		}
		shift += shift2;
	}
#endif

	RESTORE_STACK;
	return shift;
}
